芴溶解度的测定及溶液结晶法提纯芴的工艺研究

在测定芴在甲醇、乙醇、正丁醇、甲苯、邻二甲苯中溶解度的基础上,确定正丁醇是溶液结晶法提纯芴的合适溶剂。介绍了采用溶液结晶法对工业芴的提纯分离的工艺过程及不同结晶条件对产品收率和纯度的影响,确定了利用溶液结晶提纯芴的最佳工艺条件,经提纯后可使芴的纯度由89.0%提高到96.6%或由95.0%提高到97.1%。     

9-芴酮前馏分资源化研究

由芴氧化制备9-芴酮的工业生产中,会产生大量前馏分,其主要组分为:氧芴、芴、苯并[f]二氢茚、9-芴酮;企业一般将前馏分做为固废处理。本文通过高真空精馏技术、氧化技术等,成功的将前馏分中各组分分离,其含量均达到98. 0%以上,实现了前馏分的资源化利用。     

利用熔融结晶法进行芴的提纯

以工业芴为原料，实验研究了利用熔融结晶法制备精芴的工艺过程，考察了结晶降温速率、结晶终温、发汗升温速率及发汗终温对产品纯度及收率的影响，得到了利用熔融结晶方法分离提纯芴的优化工艺条件，产品纯度可达97.4%。同时根据实验结果，对芴与2-甲基氧芴两元物系的固液平衡相图进行了推测分析。     

洗油中芴的分离和精制研究进展

综述了从高温煤焦油洗油馏分中分离芴的研究现状,较为系统地总结了根据不同原理分离芴的主要方法,包括利用芴的反应活性将芴生成不同的化合物与洗油馏分中其他组分分离的化学法、利用洗油馏分中芴和其他组分的熔点、沸点和溶解度差异分离的物理法以及将单一分离方法复合起来的复合法,其中化学法主要是将芴生成9-芴甲醇或9-芴酮,再利用溶解度差异与其他组分分离,物理法主要有精馏法、结晶法(熔融结晶法、溶剂结晶法)、萃取法(传统溶剂萃取、超临界萃取),复合法主要是将精馏法与结晶法结合在一起形成的精馏-结晶法。为探究一种较为温和的从煤焦油洗油中分离芴提供一些思路和方法,为提高洗油中分离芴的效率和纯度,探索一种行之有效的工业方法提供一定的参考。     

从洗油中分离喹啉的新方法

以洗油为原料,通过精馏-共沸精馏法,研究了喹啉的分离精制。首先精馏洗油,切取不同温度段的馏分,然后分别与共沸剂乙二醇进行共沸精馏试验;在共沸精馏中,通过改变馏分与共沸剂的质量比和回流比,考察了不同条件对喹啉纯度的影响。结果表明:①精馏洗油切取喹啉馏分的较佳条件为:回流比为10∶1,切取温度范围为220~230℃;②共沸精馏的较佳条件为:回流比为10∶1,喹啉馏分与共沸剂的质量比为1∶2.4,切取温度范围为188.4~188.8℃,喹啉的纯度可达98.5%。该方法具有操作简单、步骤少、纯度高、无污染的特点。     

闪蒸-减压精馏分离苯甲酸废料

为了尽量减小资源浪费及二次污染问题,对在甲苯氧化法生产苯酚过程中产生的大量苯甲酸废料,进行了闪蒸-减压精馏分离提纯处理。废料通过闪蒸,在210℃以下得到了富集苯甲酸馏分,在220—260℃之间得到了富集苯甲酸苄酯和芴酮馏分;之后对各馏分进行高真空减压精馏,得到了苯甲酸、苯甲酸苄酯和芴酮等产品,纯度分别可达95%,91%和92%。经熔融结晶精制后,苯甲酸纯度可达99.6%,苯甲酸苄酯和芴酮纯度均达95%以上。     

氧芴精制的生产工艺研究

通过氧芴先结晶再精馏的工艺对氧芴原料进行精制。讨论了结晶所需溶剂的筛选,比较了温度和回流比对精馏过程的影响。结果表明,采用戊醇为溶剂,一次结晶可以除去苊组分。氧芴和芴含量分别为92.72%和7.28%,收率为55.1%;筛选出精馏最佳塔釜温度230℃、回流比为5∶1,得到氧芴含量为98.6%,芴含量62.1%。     

煤焦油中质洗油中提取2,6-二甲基萘的反应研究

研究以间硝基苯甲酸(m-NBA)络合结晶法从煤焦油中质洗油中分离2,6-二甲基萘(2,6-DMN),m-NBA与2,6-DMN以分子间诱导力为作用力,形成高熔点络合物,降温结晶析出。探究反应条件对2,6-DMN回收率及纯度的影响,包括:结晶温度,m-NBA添加比例。实验结果表明:物料比为1∶2,结晶温度20℃时,产品纯度高;物料比为1∶4,结晶温度30℃下,产品收率高。     

2,6-二异丙基萘的分离精制

研究了从萘与丙烯合成的异丙基萘混合物中分离、精制2,6 二异丙基萘(2,6 DIPN)的方法. 考察了精馏操作条件对精馏分离结果的影响,并研究了结晶温度及溶剂对产品纯度和收率的影响. 实验结果表明,以自行合成的烷基化产品混合物为粗产品,在1000 Pa真空度下减压精馏,收集165℃的馏出物可得到含量约50 的2,6 DIPN,将此馏分在9℃下结晶,所得晶体以乙醇为溶剂洗涤2次后,可精制出纯度为99.42 的2,6 DIPN.     

克拉霉素结晶母液回收工艺研究

通过克拉霉素结晶母液回收工艺研究提高产品的回收率,文中采用了4步过程回收克拉霉素结晶母液中的产品,包括粗品分离、二次溶剂萃取和产品结晶过程。实验结果表明:粗品分离过程中,浓缩物和水质量比为2.5∶1,过滤温度40℃时克拉霉素收率最高;溶剂萃取过程中,采用浓缩萃取液与改变温度的方法可提高产品纯度;克拉霉素的总收率达到47.8%,产品中克拉霉素和6,11-O-双甲基红霉素质量比由粗品中的约1∶1提高至52∶1。克拉霉素总回收率得到提高,给工业化生产带来较高的经济效益。     

从苊油中提取芴的研究

用精馏、结晶法可以从苊油中提取纯度≥97％的精芴,讨论了精馏、结晶和洗涤的工艺条件对芴的纯度和收率的影响,原料中的芴含量越高,回收率越高。     

溶剂结晶法制取精芴的研究

以工业芴为原料、甲苯为溶剂,研究了溶剂结晶法制取精芴的工艺过程和最佳操作条件,精芴的纯度可达９９％以上,收率达９０％。     

Influence of the composition of high-lead phosphate glasses on the location of the UV transmission edge and technological quality

This paper reports on the results of an investigation into the influence of the purity of the initial materials used for preparing vitreous lead metaphosphate, the acidity of the phosphate matrix, and the contents of additives of Group I–III and V elements and the second glass-former on the location of the UV transmission edge of simple binary and ternary lead phosphate glasses. It is shown that, even for a binary glass of the composition (mol %) 50PbO · 50P₂O₅, the location of the UV transmission edge can be shifted by ～50 nm on the wavelength scale depending on the purity of the initial reactants. The shift of the UV transmission edge toward the UV spectral range for ternary glasses containing no variable-valence elements other than lead is considerably larger than that for the high-lead phosphate glass of the previously proposed composition involving antimony, niobium, and cerium oxides. It is established that the addition of niobium oxide Nb₂O₅ to lead phosphate glasses brings about a red shift of the UV transmission edge and a change in the crystallization ability of the glasses. Niobium oxide at a content up to 1.5 mol % increases the crystallization ability of the glass, whereas a change in the niobium oxide content from 1.5 to 3.1 mol % results in a decrease in the crystallization ability. It is demonstrated that the crystallization ability of high-lead phosphate glasses increases at a boron oxide content higher than 5 mol %.     

Melting and crystallization behaviors of compatibilized poly(trimethylene terephthalate)/acrylonitrile–butadiene–styrene blends

The melting and crystallization behaviors of poly(trimethylene terephthalate) (PTT)/acrylonitrile–butadiene–styrene (ABS) blends were investigated with and without epoxy or styrene–butadiene–maleic anhydride copolymer (SBM) as a reactive compatibilizer. The existence of two separate composition-dependent glass-transition temperatures (T_g's) indicated that PTT was partially miscible with ABS over the entire composition range. The melting temperature of the PTT phase in the blends was also composition dependent and shifted to lower temperatures with increasing ABS content. Both the cold crystallization temperature and T_g of the PTT phase moved to higher temperatures in the presence of compatibilizers, which indicated their compatibilization effects on the blends. A crystallization exotherm of the PTT phase was noticed for all of the PTT/ABS blends. The crystallization behaviors were completely different at low and high ABS contents. When ABS was 0–50 wt %, the crystallization process of PTT shifted slightly to higher temperatures as the ABS content was increased. When ABS was 60 wt % or greater, PTT showed fractionated crystallization. The effects of both the epoxy and SBM compatibilizers on the crystallization of PTT were content dependent. At a lower contents of 1–3 wt % epoxy or 1 wt % SBM, the crystallization was retarded, whereas at a higher content of 5 wt %, the crystallization was accelerated. The crystallization kinetics were analyzed with a modified Avrami equation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

螯合剂对湿法磷酸制备磷酸二氢钾结晶过程影响

湿法磷酸生产成本低,但杂质含量高,以湿法磷酸为原料制得的磷酸二氢钾(KDP)产品质量低。研究利用中和法,以杂质含量高的工业湿法磷酸为原料,制备柱状大颗粒磷酸二氢钾晶体。研究了螯合剂用量、降温速率和搅拌速率对磷酸二氢钾结晶过程的影响,考察了磷酸二氢钾的质量分数、收率、结晶速率和晶体形貌等指标,并进行了母液循环实验。研究结果表明：螯合剂能有效消除杂质离子对结晶过程的抑制作用。结晶的最适宜工艺条件为螯合剂用量0.70%、搅拌速率100 r·min^-1、降温速率0.1℃·min^-1。在此条件下得到的磷酸二氢钾晶体外观为柱状大颗粒,质量分数99.91%,平均粒度1.38 mm,结晶速率0.128 g·min^-1,达到肥料级磷酸二氢钾优等品标准(HG/T 2321—2016);其中磷的单次收率49.86%。母液循环生产的磷酸二氢钾晶体质量分数、晶型和收率等指标全部达标。     

结晶法提纯N-乙烯基吡咯烷酮的工艺

对于应用于食品和医药等领域的N-乙烯基吡咯烷酮聚合物,要求N-乙烯基吡咯烷酮单体的纯度高于99.9%,但精馏法往往达不到要求。为了解决这个问题,本文采用结晶法对纯度为99.5%的工业级N-乙烯基吡咯烷酮进行提纯以制备纯度高于99.9%的医药级产品。考察了晶种添加量、晶种添加温度、降温速率、结晶终温、养晶时间、升温速率、发汗终温和发汗时间对最终产品的收率和纯度的影响,并确定了较为适宜的工艺条件：晶种添加量为原料质量的0.1%,晶种添加温度为11℃,降温速率为6℃/h,结晶终温为6℃,养晶时间为20min,升温速率为6~8℃/h,发汗终温为12℃,发汗时间为30min。在这些条件下通过单级结晶就可以将纯度为99.5%的N-乙烯基吡咯烷酮原料提纯至99.95%以上,收率大于74.5%。该方法相对其他分离方法具有较为明显的优势。     

Synthesis and characterization of magnesium hydroxide by batch reaction crystallization

Magnesium hydroxide with high purity and uniform particle size distribution was synthesized by the direct precipitation method using MgCl₂ and NaOH as reactive materials and NaCl as additive to improve the crystallization behavior of the product. The particle size distribution, crystal phase, morphology, and surface area of magnesium hydroxide were characterized by Malvern laser particle size analyzer, X-ray diffraction (XRD), scanning electron microscope (SEM) and Branauer-Emmett-Teller (BET) method, respectively. The purity of products was analyzed by the chemical method. The effects of synthesis conditions on the particle size distribution and water content (filtration cake) of magnesium hydroxide were investigated. The results indicated that feeding mode and rate, and reaction temperature had important effects on water content and the particle size distribution of the product, and sodium chloride improved the crystallization behavior of magnesium hydroxide. The ball-like magnesium hydroxides with the particle size distribution of 6.0–30.0 μm and purity higher than 99.0% were obtained. This simple and mild synthesis method was promising to be scaled up for the industrial production of magnesium hydroxide.     

Non-isothermal crystallization kinetics of calcium carbonate-filled β-crystalline phase polypropylene composites

The non-isothermal crystallization behaviour of high purity β-phase and α-phase polypropylene (PP) and their calcium carbonate-filled composites was investigated by means of differential scanning calorimetry. High purity β-PP polymer was prepared by adding an effective β-nucleator consisting of equal amounts of pimelic acid and calcium stearate. The crystallization temperature and crystallization rate coefficient of pure β-PP polymer were considerably higher than those of the α-PP polymer. This was due to the β-PP polymer containing nucleating agents, which act as nuclei for β-spherulites. The calcium carbonate content had little or no effect on the crystallization rate coefficient and Ozawa exponent of the β-phase PP in the composites. On the other hand, the crystallization temperature, crystallization rate coefficient and Ozawa exponent of the α-phase PP composites depended on the calcium carbonate loading. The effect of calcium carbonate additions on the crystallization of α-PP and β-PP is discussed. ©1997 SCI